The ultra-sound sensor measures physical parameters such as location, speed and distance by emitting and receiving an ultra-sound wave. In an ordinary electronic device using an ultra-sound sensor, a micro-processor generates a driving voltage/current signal according to the frequency and magnitude of the to-be-emitted ultra-sound wave for driving the ultra-sound emitter to emit an ultra-sound wave. Then, the ultra-sound receiver receives the reflected ultra-sound wave and the micro-processor further converts the received ultra-sound wave into a voltage/current signal. Normally, the ultra-sound sensor has both functions of receiving and emitting ultra-sound waves.
In the application of ultra-sound sensor, two or more ultra-sound sensors can be used in detection. When two or more ultra-sound sensors are used, normally, one ultra-sound sensor is used for emitting an ultra-sound wave and another ultra-sound sensor is used for receiving a reflected ultra-sound wave. However, as the radiation sound fields and the distances between the ultra-sound sensors are too close, the ultra-sound receiver may receive not only the reflected ultra-sound wave but also the ultra-sound wave directly transmitted from the emitter on the lateral side, hence resulting in crosstalking. Thus, the ultra-sound receiver may mistake the crosstalk signal as a reflected ultra-sound wave and may lead to erroneous judgment or control. For example, in distance measurement, the crosstalk signal may make the distance-measurement function abnormal or erroneous judgment. Therefore, in general, a special controlling method is used to avoid or exclude the occurrence of crosstalk.
However, crosstalk does not result negative effect only. Crosstalk may be applied in control to provide more control functions without changing hardware architecture.